Radio antenna



(232033 June 14, 1960 R. w. BUNCE 2,941,207

RADIO ANTENNA Filed Aug. 15, 1955 P0010 R4010 Recs/V51? EEcE/VEI? INVENTGR. ROGER W. BL/Nc-E 4T TOE/VEY-S United States Patent RADIO ANTENNA Roger W. Bunce, Burlingame, Calif., assignor to The Robert Dollar Company, San Francisco, Calif., a corporation Filed Aug. 15, 1955, Ser. No. 528,315

1 Claim. (Cl. 343--900) This invention relates to radio communication and particularly to an antenna for the receiving of radio frequency energy. In small radio receivers of the type designed to receive a single predetermined frequency and to be carried on the person such as the receiver disclosed in the United States Reissue Patent No. 23,651 to R. R. Florac, it is desirable and often essential that the number and size of electronic tubes, diodes, transistors, and the like be kept to a minimum to conserve both power and space. The antenna system for such a receiver should be sufiiciently small to be conveniently carried on the person and in addition must be efficient enough to supply the receiver with an adequate input signal. Accordingly an object of this invention is to provide such an efiicient antenna system which is small enough to be carried on the person.

Another object of this invention is to provide an improved tuned antenna system which is adaptable for use in miniature radio receivers designed for operation on a single frequency.

A further object of this invention is to provide a resonate antenna system in which the physical length of the antenna structure is packaged in a small area.

Yet still another object is to provide an antenna structure which is arranged to resonate at a pre-determined frequency employing a single wire bunched in closely associated parallel stretches that are separated from one another only by a thin film of electrical insulation integral with the Wire.

The above and other objects and advantages of my invention will best be understood by referring to the following detailed specification of certain selected and preferred embodiments thereof chosen by way of illustration and not limitation and by a like reference to the accompanying drawings forming a part hereof in which,

In the drawings:

Fig. 1 is a diagrammatic view of the antenna system of the invention.

Fig. 2 is a diagrammatic view of a variation of the antenna of Fig. 2.

Fig. 3 is a vertical elevational view of the invention.

Fig. 4 is a sectional view taken on line 4-4 of Fig. 3.

In Fig. 1 an antenna 9 is formed of a thin enameled wire 15 wound or lapped to form a plurality of parallel stretches 16 which traverse back and forth and which are of approximately equal length. The stretches 16 are housed in a length of tubular insulation 17 in tightly bunched intimate contact with each other. (The figure is illustrative of the elements and does not show the stretches and tubular insulation in bunched relationship. See Figs. 3 and 4). The tube 17 maybe any small nonconductive tube; however, it has been found convenient to use short lengths of wire covering known in the art as spaghetti. The tube 17 forms a protective casing for the wire 15 in addition to holding the stretches 16 in the proper closely associated bunched union. One end of wire 1.5 connects directly to the input of a radio receiver ice 19 which is arranged to receive radio frequency signals of a predetermined frequency.

To be of optimum efliciency for the operation frequency of the receiver 19 the antenna 9 must be either tuned to the wavelength of that frequency or to a harmonic thereof. The frequency at which the antenna 9 will resonate is dependent upon the number and the physical length of the stretches 16. Fewer or shorter stretches 16 will cause the antenna to resonate at a higher frequency while a greater number or a greater length of the stretches 16 will cause the antenna 9 to resonate at a lower frequency.

The physical shape of the antenna 9 creates a large electrical length of wire which is compacted into an extremely small area therein providing an antenna circuit which will resonate at relatively low frequencies as compared with antennas available in the prior art, and has been found extremely effective in the reception of radio frequency signals. The antenna 9 may be constructed with economy and with sufficiently small outside dimensions to be no larger than a short length of electrical wire.

In schematic Fig. 2 is illustrated an antenna substantially similar to the structure described above in connection with Fig. 1. The antenna of Fig. 2 is provided with an additional stretch 20 of wire extending from the last stretch 16. The additional external stretch 20 provides a somewhat greater cross-sectional area and must be considered in determining the electrical length of the antenna in order to obtain resonance at the operation frequency. The stretch 20 may extend directly upwardly as a whip.

The insulating tube 9 affords not only a ready means to retain the bunched stretches in desired position but also imparts a desired degree of stiffening or rigidity to the antenna.

In practice, the antenna may be formed by lapping a predetermined number of stretches of wire around a suitable jig or mandrel and then feeding or pulling the solapped wire through a desired length of insulation tubing. Preferably the fit of lapped wire and tubing should be snug.

It will be understood that this invention is not limited to the specific embodiments herein illustrated and described and that the following claim is intended to cover all changes and modifications which do not depart from the spirit and the true scope of the invention.

What is claimed is:

In a tuned antenna the combination of: a single thin conductor folded over into a plurality of elongated parallel adjacent straight stretches of equal length; means electrically insulating said straight stretches from each other; a straight, semi-rigid, self-sustaining, nonconductive elongated tubular member; said elongated stretches being positioned within said tubular member in a tightly bunched relationship so as to form a substantially solid rod; said elongated tubular member being substantially the entire length of said straight stretches.

References Cited in the file of this patent UNITED STATES PATENTS 1,792,964 Brooks et al Feb. 17, 1931 1,876,318 Senter et al. Sept. 6, 1932 2,005,805 Round June 25, 1935 2,049,744 Mann Aug. 4, 1936 2,083,260 Godlay Apr. 10, 1937 2,307,805 Schnell Jan. 12, 1943 2,346,654 Leuthold Apr. 18, 1944 2,647,211 Smeby July 28, 1953 2,725,473 Darling Nov. 29, 1955 FOREIGN PATENTS 490,414 Great Britain July 21, 1938 

